Holley 4160 to 4150 conversion

HI CHUCK! I THINK THAT YOU COULD JUST EXCHANGE THE SECONDARY AND LEAVE THE PRIMARY IN PLACE, YOUR GOING TO HAVE TO TUNE THE JETS ANYWAY. AT THE MOST, THE GASKETS MAY BE SLIGHTLY DIFFERENT. I HAVE THOUGHT OF DOING THE SAME SWAP MYSELF, IT'S A GREAT IDEA, SURE SAVES BUYING AN ALL NEW CARBURATER! ESPECIALLY THE CENTER PIVOT FLOATS. WITH THE AGGRESSIVE "ROAD-RACE" STYLE OF DRIVING THAT WE ALL LOVE TO PERFORM, THEY ARE BETTER THAN THE SIDE PIVOTS. EVEN MORE-SO WHEN WE ADD IN HARD ACCELERATING AND BRAKING. AND THE DUAL FUEL INLETS WILL BE AN IMPROVEMENT WHEN YOU HIT THOSE HI REVS. BUT YOU ALREADY KNOW THIS! HOW DO YOU GET THOSE SPECIAL SCREWS OUT OF THE SECONDARY METERING PLATE, WITHOUT HAVING TO HUNT DOWN THE CORRECT DRIVER?? GOOD LUCK WITH IT! MARLIN.

I'd just add the secondary metering block, and be real careful to use gaskets that match up with the carb body AND the metering block. You may have to add a hole or two to do this from your stock of gaskets, although I recommend using non-Holley gaskets so you can re-use the gaskets. As you know, Holley gsaskets are non-leak because they glue themselves to the metal parts and must be chsieled off. Aftermarket gaskets don't behave this way. Your 4777 secondary float bowl has passages built in for a secondary accelerator pump; be sure you don't get a leak here if you choose to use or not to use the 2nd pump.

MARLIN,

I HAVE THE "CLUTCH-HEAD" SCREWDRIVER.
MADE BY STANLEY.

CHUCK